FLUID MECHANICS

PART-2

MADE EASY GATE HANDWRITTEN CLASSROOM NOTES

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Fluid Mechanics Made Easy GATE Handwritten Classroom Notes Part-2

PLEASE NOTE : WE PROVIDE ONLY VERIFIED NOTES AND MATERIALS. ALL THE OTHER NOTES WHICH ARE AVAILABLE IN THE INTERNET WITH THE NAME MADE EASY CIVIL NOTES ARE FAKE AND ARE NORMAL CLASSROOM NOTES OF SOME COLLEGE. WE ALWAYS TRY TO BRING OUT QUALITY NOTES FOR FREE AND FOR THE SAKE OF STUDENTS WHO ARE REALLY WORKING HARD DAY AND NIGHT AIMING GOOD GATE/IES RANKS.

Dynamics of Fluid Flow :

Study of fluid particle motion with the consideration of basic cause of motion, i.e force. It is studies taking mass of fluid as system. The Newton’s second law of motion is applied to get the Momentum Equation.

Hydraulic Gradient Line :

It is the line joining the points representing the values or levels of piezometric heads at the various cross sections of the pipe in the direction of flow.

1. Total energy line always goes down in direction of flow until and unless external energy is supplied in between.
2. Hydraulic gradient line (HGL) may go up and down in the direction of flow (in case of sudden contraction or expansion)
3. Hydraulic Gradient Line is always below the total energy line and the vertical gap or difference between these two lines at any section represents the value of Kinetic head at that section. Thus in the pipe of uniform diameter, hydraulic gradient line (HGL) will always be parallel to Total Energy Line.

Non Dimensional Numbers in Fluid Flow System:

Reynolds Number : It is defined as ratio of inertia forces to viscous forces. This number plays very important role in those areas where viscosity effects are predominant.
Example : Boundary layer flows like pipe flows.

Eulers Number : It is defined as square root of ratio of inertia force to pressure force. This number becomes highly significant in those areas where pressure forces are severely dominant. Example : Pipe flows pressure energy used to increase total head.

Froudes Number : It is defined as the square root of the ratio of inertia force to gravity force. It becomes important in those regions where gravity forces are predominant. Example : Open channel flows, flow through spillways, rivers, canals.

Weber Number : It is defined as square root of the ratio of inertia force to surface tension force. It becomes important in capillary flows.

Mach Number : It is defined as square root if the ratio of inertia force to compressibility force (elastic force). This number becomes important in compressible flow system.